Doctors warn against ditching specs Superman-style as fears remain on safety of paediatric Lasik

Ana Hidalgo-Simón MD, PhD
in Gatwick

SUPERMAN may pocket his specs to rescue the virtuous from devastating earthquakes but laser refractive surgery should not be used as a means of supplanting conventional glasses in paediatric cases, said surgeons at a cornea conference.

“Refractive surgery is well established among adults, but its use remains controversial in children due to concerns about safety and predictability. Our use of paediatric Lasik is purely for therapeutic purposes and there is no intention to use it to help children to get rid of their glasses,” Deepinder K Dhaliwal MD said.

But there are some situations in which the paediatric population can benefit from refractive surgery, according to Dr Dhaliwal. One of these is the treatment of anisometropic amblyopia after either a history of poor compliance or a failure to improve with conventional therapy using spectacles or contact lenses with occlusion.

Amblyogenic refractive error can develop in children with a myopic difference greater than 3.0 D or with hyperopic or astigmatic difference greater than 2.0 D. Conventional amblyopia treatment is successful in the majority of cases but even here deterioration of visual acuity can occur at a later stage, she said.

“Paediatric Lasik can provide rapid recovery, rarely causes haze and is essentially painless. We were initially worried about intraoperative and postoperative complications. Treating paediatric eyes requires special considerations and we cannot just consider them smaller eyes in smaller people,” she stressed.

Dr Dhaliwal noted that topical anaesthesia could only be used in co-operative children. IV anaesthesia has also been used, but her group most often uses general anaesthesia. She said an important lesson that they learned is never to use anaesthesia through a mask because the aesthetic gases can cause the laser to malfunction if leakage occurs.
She reported that fixation and centration techniques also need to be adjusted; she uses surgeon fixation facilitated by a suction ring.

The microkeratome also needs to be selected with care. Dr Dhaliwal’s unit performed the operations with the VISX Star S2 Excimer laser and the Moria Carriazo-Barraquer microkeratome. They performed Lasik on the more myopic, amblyopic eye. The youngest patient she operated on was five-years-old.

Dr Dhaliwal’s experience includes performing Lasik in three girls and two boys, aged five to eight years. The patients’ mean spherical equivalent (SE) ranged from -5.0 D to -13.63 D, with a mean of -8.83 D; preoperative BCVA was 20/60 in two children; and 20/200, 20/400 and count fingers in the other three patients. The patients had failed previous repeated attempts at correction with spectacles or contact lenses.

Lasik was performed on the more myopic eye. The surgery was successful in reducing myopia in all eyes. Despite some under-corrections, all were within 3.0 D of the fellow eye. Refractions remained stable between three months and one year.
At the last visit, cycloplegic SE values ranged from -0.25 D to -6.75 D, with a mean of -2.20 D. BCVA ranged from 20/30 to 20/400 and was improved from baseline in three children and unchanged in two. The best improvements in BCVA, however, were obtained in children with less dense amblyopia, preoperatively.

“You theoretically have a window of opportunity from birth to about age nine where, if you correct the vision and they have a clear image formed, their visual pathways will develop appropriately and they can potentially have 20/20 vision. Apart from those limits, the jury is still out on the optimal age for intervention,” she said.

Overall, she said these results were encouraging, although the numbers are small. Even in some cases where the surgery did not produce objective success for visual improvement, the children were very happy to be able to use normal spectacles postoperatively.

Dr Dhaliwal closed her lecture by saying that treatment of paediatric anisomyopia with Lasik may be an effective therapy to be added to current treatments of this amblyogenic condition in selected cases, but further and larger studies are required.
In the lively discussion that followed the paediatric cornea presentations, the issue of wider application of refractive surgery in children was raised.

Despite a general agreement that these procedures should be kept for therapeutic purposes only, some attendants raised the possibility of future potential demands for refractive surgery in children with relatively modest errors to get rid of spectacles.
While some cautioned that the can of worms should never be opened on paediatric Lasik, others argued that peer and parent pressure to dispose of spectacles will be enormous.

As one contributor pointed out, the game for childrens’ spectacles may not yet be up as long as modern boy hero Harry Potter keeps his pair firmly on the bridge of his nose — and x-ray sighted Superman is confined to cartoon history.

Deepinder K Dhaliwal MD
University of Pittsburgh School of Medicine, US
Email: dhaliwaldk@msx.upmc.edu

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